What is the result of subtracting the second equation from the first?
−3x + 2y = 7
−3x − 2y = 4

An an average person has 6×10 by the power of two as many red blood cells as white blood cells a small sample of the blood has 7×10 by the power of three white blood cells about how many red blood cells are in the sample

The perimeter of a triangle is 69 cm. the first is 5 cm shorter than the second side. the third side is twice as long the first side. find the length of each side

Change negative exponents to positive, then solve